Colbourn, C. J., A. D. Forbes, M. J. Grannell, T. S. Griggs, P. Kaski, P. R. J. Östergård, D. A. Pike, and O. Pottonen. “Properties of the Steiner Triple Systems of Order 19”. The Electronic Journal of Combinatorics, Vol. 17, no. 1, July 2010, p. R98, doi:10.37236/370.